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Proteins that oxidize extracellular substrates in Gram-positive bacteria are poorly understood. Ferrimicrobium acidiphilum is an actinobacterium that respires aerobically on extracellular ferrous ions at pH 1.5. In situ absorbance measurements were conducted on turbid suspensions of intact Fm. acidiphilum using an integrating cavity absorption meter designed for that purpose. Initial velocity kinetic studies monitored the appearance of product ferric ions in the presence of catalytic quantities of cells. Cell-catalyzed iron oxidation obeyed the Michaelis-Menten equation with Km and Vmax values of 71 μM and 0.29 fmol/min/cell, respectively. Limited-turnover kinetic studies were conducted with higher concentrations of cells to detect and monitor changes in the absorbance properties of cellular redox proteins when the cells were exposed to limited quantities of soluble reduced iron. A single a-type cytochrome with reduced absorbance peaks at 448 and 605 nm was the only redox-active chromophore that was visible as the cells respired aerobically on iron. The reduced cytochrome 605 exhibited mathematical and correlational properties that were consistent with the hypothesis that oxidation of the cytochrome constituted the rate-limiting step in the aerobic respiratory process, with a turnover number of 35 ± 2 s−1. Genomic and proteomic analyses showed that Fm. acidiphilum could and did express only two a-type heme copper terminal oxidases. Cytochrome 605 was associated with the terminal oxidase gene that is located between nucleotides 31,090 and 33,039, inclusive, in the annotated circular genome of this bacterium. IMPORTANCE The identities and functions of proteins involved in aerobic respiration on extracellular ferrous ions at acidic pH are poorly understood in the four phyla of Gram-positive eukaryotes and archaea where such activities occur. In situ absorbance measurements were conducted on Fm. acidiphilum as it respired on extracellular iron using an integrating cavity absorption meter that permitted accurate optical measurements in turbid suspensions of the intact bacterium under physiological conditions. The significance of these measurements is that they permitted a direct spectrophotometric examination of the extents and rates of biological electron transfer events in situ under noninvasive physiological conditions without disrupting the complexity of the live cellular environment. One thing is certain: one way to understand how a protein functions in an intact organism is to actually observe that protein as it functions in the intact organism. This paper provides an example of just such an observation.

Metal-dependent lysine deacetylases (KDACs) are involved in regulation of numerous biological and disease processes through control of post-translational acetylation. Characterization of KDAC activity and substrate identification is complicated by inconsistent activity of prepared enzyme and a range of multi-step purifications. We describe a simplified protocol based on two-step affinity chromatography. The purification method is appropriate for use regardless of expression host, and we demonstrate purification of several representative members of the KDAC family as well as a selection of mutated variants. The purified proteins are highly active and consistent across preparations.

Absorbance spectra were collected on twelve different live microorganisms, representing six phyla, as they respired aerobically on soluble iron at pH 1.5. A novel integrating cavity absorption meter was employed that permitted accurate absorbance measurements in turbid suspensions that scattered light. Illumination of each microorganism yielded a characteristic spectrum of electrochemically reduced colored prosthetic groups that gradually reoxidized when the limiting ferrous ions were depleted. A total of six different patterns of reduced-minus-oxdized difference spectra were observed. Three different spectra were obtained with members of the Gram-negative eubacteria. Acidithiobacillus, representing Proteobacteria, yielded a spectrum in which cytochromes a and c and a blue copper protein were all prominent. Acidihalobacter, also representing the Proteobacteria, yielded a spectrum in which both cytochrome b and a long-wavelength cytochrome a were clearly visible. Two species of Leptospirillum, representing the Nitrospirae, both yielded spectra that were dominated by an unusuall cytochrome with a reduced peak at 579 nm. Sulfobacillus and Alicyclobacillus, representing the Gram-positive Firmicutes, both yielded spectra dominated by a-type cytochromes. Acidimicrobium and Ferrimicrobium, representing the Gram-postitive Actinobacteria, also yielded spectra dominated by a-type cytochromes. Acidiplasma and Ferroplasma, representing the Euryarchaeota, both yielded spectra dominated by a ba3-type of cytochrome. Metallosphaera and Sulfolobus, representing the Crenarchaeota, both yielded spectra dominated by the same novel cytochrome as that observed in the Nitrospirae and a new, heretofore unrecognized redox-active prosthetic group with a reduced peak at around 485 nm. These observations are consistent with the hypothesis that individual acidophilic microorganisms that respire aerobically on iron utilize one of at least six different types of electron transfer pathways that are characterized by different redox-active prosthetic groups. In situ absorbance spectroscopy is shown to be a useful complement to existing means of investigating the details of energy generation in intact microorganisms under physiological conditions.

Alcohol abuse has been associated with increased susceptibility to pulmonary infection. It is not fully defined how alcohol contributes to the host defense compromise. Here primary human airway epithelial cells were cultured at an air-liquid interface to form a differentiated and polarized epithelium. This unique culture model allowed us to closely mimic lung infection in the context of alcohol abuse by basolateral alcohol exposure and apical live bacterial challenge. Application of clinically relevant concentrations of alcohol for 24 h did not significantly alter epithelial integrity or barrier function. When apically challenged with viable Klebsiella pneumoniae, the cultured epithelia had an enhanced tightness which was unaffected by alcohol. Further, alcohol enhanced apical bacterial growth, but not bacterial binding to the cells. The cultured epithelium in the absence of any treatment or stimulation had a base-level IL-6 and IL-8 secretion. Apical bacterial challenge significantly elevated the basolateral secretion of inflammatory cytokines including IL-2, IL-4, IL-6, IL-8, IFN-γ, GM-CSF, and TNF-α. However, alcohol suppressed the observed cytokine burst in response to infection. Addition of adenosine receptor agonists negated the suppression of IL-6 and TNF-α. Thus, acute alcohol alters the epithelial cytokine response to infection, which can be partially mitigated by adenosine receptor agonists.

Optimal microbicidal activity of human polymorphonuclear leukocytes (PMN) relies on the generation of toxic agents such as hypochlorous acid (HOCl) in phagosomes. HOCl formation requires H2O2 produced by the NADPH oxidase, myeloperoxidase derived from azurophilic granules, and chloride ion. Chloride transport from cytoplasm into phagosomes requires chloride channels which include cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated chloride channel. However, the phagosomal targeting of CFTR in PMN has not been defined. Using human peripheral blood PMN, we determined that 95-99% of lysosomal-associated membrane protein 1 (LAMP-1)-positive mature phagosomes were CFTR positive, as judged by immunostaining and flow cytometric analysis. To establish a model cell system to evaluate CFTR phagosomal recruitment, we stably expressed enhanced green fluorescent protein (EGFP) alone, EGFP-wt-CFTR and EGFP-DF508-CFTR fusion proteins in promyelocytic PLB-985 cells, respectively. After differentiation into neutrophil-like cells, CFTR presentation to phagosomes was examined. EGFP-wt-CFTR was observed to associate with phagosomes and colocalize with LAMP-1. Flow cytometric analysis of the isolated phagosomes indicated that such a phagosomal targeting was determined by the CFTR portion of the fusion protein. In contrast, significantly less EGFP-DF508-CFTR was found in phagosomes, indicating a defective targeting of the molecule to the organelle. Importantly, the CFTR corrector compound VRT-325 facilitated the recruitment of DF508-CFTR to phagosomes. These data demonstrate the possibility of pharmacologic correction of impaired recruitment of mutant CFTR, thereby providing a potential means to augment chloride supply to the phagosomes of PMN in patients with cystic fibrosis to enhance their microbicidal function.

Biosynthesis of hypochlorous acid (HOCl), a potent anti-microbial oxidant, in phagosomes is one of the chief mechanisms employed by polymorphonuclear neutrophils (PMNs) to combat infections. This reaction, catalyzed by myeloperoxidase, requires chloride anion (Cl−) as a substrate. Thus, Cl− availability is a rate-limiting factor that affects neutrophil microbicidal function. Our previous research demonstrated that defective CFTR, a cAMP-activated chloride channel, present in cystic fibrosis (CF) patients leads to deficient chloride transport to neutrophil phagosomes and impaired bacterial killing (Painter et al., 2008 & 2010). To confirm this finding, here we used RNA interference against this chloride channel to abate CFTR expression in the neutrophil-like cells derived from HL60 cells, a promyelocytic leukemia cell line, with DMSO. The resultant CFTR deficiency in the phagocytes compromised their bactericidal capability, thereby recapitulating the phenotype seen in CF patient cells. The results provide further evidence suggesting that CFTR plays an important role in phagocytic host defense.

J’ai éprouvé, récemment, l’expérience du cancer depuis l’autre perspective : j’ai ainsi eu le privilège de partager l’expérience du cancer vécue par une personne très chère. C’est tandis que je traversais cette expérience, ce cheminement main dans la main, coeur à coeur et âme à âme avec mon mari, que j’ai véritablement appris ce que je pensais déjà savoir à propos de ce que les infirmières en oncologie font pour soulager la souffrance, pour aider à guérir et pour alléger le fardeau du cancer. Le but de cet article est de fournir aux infirmières en oncologie une fenêtre sur le vécu d’un mourant atteint du cancer et de confirmer ce que nous savons, de décrire ce que nous ne savons pas et de remettre en question, dans une optique bienveillante, quelques-unes de nos suppositions afin que nous devenions de meilleures disciples de nos maîtres véritables, les patients.

Tissue injury enhances homing and engraftment of mesenchymal stem cells (MSCs). However, the mechanisms by which MSCs sense the signals released by injured tissues and migrate toward injury sites have not been fully defined. In the current report, we investigated whether human MSCs express the N-formyl peptide receptor (FPR) and the formyl peptide receptor-like-1 (FPRL1). These receptors bind to N-formylated peptides by which phagocytes migrate to inflammatory sites and fibroblasts repopulate wounds to remodel the damaged tissues. Reverse-transcription polymerase chain reaction (PCR) demonstrated that MSCs express both FPR and FPRL1 at the transcriptional level. Flow cytometric analyses revealed expression of both receptors at the protein level. Fusion of the enhanced green fluorescence protein (eGFP) to the C terminus of each receptor showed localization to the cell surface. Moreover, MSCs responded to stimulation by N-formyl methionyl leucyl phenylalanine (fMLP), a prototypic N-formyl peptide, demonstrating rapid intracellular calcium mobilization that can be blocked by pertussis toxin or cyclosporin H. It is noteworthy that the fMLP-stimulated MSCs had an enhanced adhesion to extracellular matrix protein-coated surfaces. In addition, MSCs migrated toward gradients of increasing fMLP concentration, indicating that the receptors were functionally involved in positive chemotaxis to formylated peptides. Therefore, the N-formyl peptide receptors present in MSCs may play an important role in signaling stem cell adhesion, migration, and homing to injured and inflamed tissue for repair. Such a mechanism could potentially be exploited to direct the stem cells to target specific tissue sites, such as cystic fibrosis lungs, for therapy.Disclosure of potential conflicts of interest is found at the end of this article.

Recently, I experienced cancer from the other side: I have had the privilege of sharing the cancer experience with an intimate other. It was while I lived through this experience, this hand-in-hand, heart-to-heart and soul-by-soul walk with my husband that I really learned what I thought I already knew about how oncology nurses alleviate suffering, help heal and lessen the burden of the cancer illness. The purpose of this paper is to provide the oncology nurse with a portal into a lived experience of a person dying of cancer and to confirm what we do know, describe what we do not know and to lovingly challenge some of our assumptions so that we may become better students of our real teachers: our patients.

Electron transfer reactions among three prominent colored proteins in intact cells of Acidithiobacillus ferrooxidans were monitored using an integrating cavity absorption meter that permitted the acquisition of accurate absorbance data in suspensions of cells that scattered light. The concentrations of proteins in the periplasmic space were estimated to be 350 and 25 mg/ml for rusticyanin and cytochrome c, respectively; cytochrome a was present as one molecule for every 91 nm(2) in the cytoplasmic membrane. All three proteins were rapidly reduced to the same relative extent when suspensions of live bacteria were mixed with different concentrations of ferrous ions at pH 1.5. The subsequent molecular oxygen-dependent oxidation of the multicenter respiratory chain occurred with a single macroscopic rate constant, regardless of the proteins' in vitro redox potentials or their putative positions in the aerobic iron respiratory chain. The crowded electron transport proteins in the periplasm of the organism constituted an electron conductive medium where the network of protein interactions functioned in a concerted fashion as a single ensemble with a standard reduction potential of 650 mV. The appearance of product ferric ions was correlated with the reduction levels of the periplasmic electron transfer proteins; the limiting first-order catalytic rate constant for aerobic respiration on iron was 7,400 s(-1). The ability to conduct direct spectrophotometric studies under noninvasive physiological conditions represents a new and powerful approach to examine the extent and rates of biological events in situ without disrupting the complexity of the live cellular environment.

Human neutrophils synthesize hypochlorous acid, a nonradical oxidant, as one of the antimicrobial agents to kill phagocytosed pathogens within phagolysosomes. The production of HOCl is catalyzed by myeloperoxidase using chloride anions (Cl-). Even though various approaches have been documented to measure cytosolic Cl- concentrations, direct detection of phagolysosomal free Cl- in a real-time fashion is not available. Here we report the development of a new dual-labeled fluorescent probe by conjugation of the chloride-sensitive 6-methoxyquinoline and chloride-insensitive tetramethylrhodamine to the zymosan particles. On the surface of the zymosan particles, the chloride-sensitive fluorophore responded linearly to chloride concentrations when plotted according to the Stern-Volmer collisional quenching equation and the chloride-insensitive fluorophore served as an internal reference. After phagocytosis into neutrophils, the probe was able to monitor intraphagosomal chloride levels authentically. Human neutrophils in the medium containing 122 mM chloride had a phagolysosomal chloride level of 73.3 +/- 12.2 mM (N = 5). In contrast, the neutrophils in a chloride-free isoosmotic medium had a chloride level of 6.6 +/- 1.9 mM (N = 5) in the phagolysosomal compartment. These data clearly demonstrated that the extracellular chloride levels affect intraphagolysosomal chloride levels in human neutrophils. Moreover, when the extracellular chloride concentration was switched from high level (122 mM) to low level (0 mM) or vice versa, the probe demonstrated complete reversibility. The data indicate that the new zymosan-conjugated chloride probe described here can be used as an indicator for measurement of the free chloride level within the phagolysosomes of neutrophils and other phagocytic cell types.

Alcohol abuse has been associated with increased susceptibility to pulmonary infection. It is not fully defined how alcohol contributes to the host defense compromise. Here primary human airway epithelial cells were cultured at an air-liquid interface to form a differentiated and polarized epithelium. This unique culture model allowed us to closely mimic lung infection in the context of alcohol abuse by basolateral alcohol exposure and apical live bacterial challenge. Application of clinically relevant concentrations of alcohol for 24 hours did not significantly alter epithelial integrity or barrier function. When apically challenged with viable Klebsiella pneumoniae, the cultured epithelia had an enhanced tightness which was unaffected by alcohol. Further, alcohol enhanced apical bacterial growth, but not bacterial binding to the cells. The cultured epithelium in the absence of any treatment or stimulation had a base-level IL-6 and IL-8 secretion. Apical bacterial challenge significantly elevated the basolateral secretion of inflammatory cytokines including IL-2, IL-4, IL-6, IL-8, IFN-γ, GM-CSF, and TNF-α. However, alcohol suppressed the observed cytokine burst in response to infection. Addition of adenosine receptor agonists negated the suppression of IL-6 and TNF-α. Thus, acute alcohol alters the epithelial cytokine response to infection, which can be partially mitigated by adenosine receptor agonists.

Cystic fibrosis (CF), the most prevalent, fatal genetic disorder in the Caucasian population, is caused by mutations of CF transmembrane conductance regulator (CFTR). The mutations of this chloride channel alter the transport of chloride and associated liquid and thereby impair lung defenses. Patients typically succumb to chronic bacterial infections and respiratory failure. Restoration of the abnormal CFTR function to CF airway epithelium is considered the most direct way to treat the disease. In this report, we explore the potential of adult stem cells from bone marrow, referred to as mesenchymal or marrow stromal stem cells (MSCs), to provide a therapy for CF. We found that MSCs possess the capacity of differentiating into airway epithelia. MSCs from CF patients are amenable to CFTR gene correction, and expression of CFTR does not influence the pluripotency of MSCs. Moreover, the CFTR-corrected MSCs from CF patients are able to contribute to apical Cl - secretion in response to cAMP agonist stimulation, suggesting the possibility of developing cell-based therapy for CF. The ex vivo coculture system established in this report offers an invaluable approach for selection of stem-cell populations that may have greater potency in lung differentiation.

Five pockets of open cells (POCs) are studied using aircraft flights from the VOCALS Regional Experiment, conducted in October and November 2008 over the southeast Pacific Ocean. Satellite imagery from the geostationary satellite GOES-10 is used to distinguish POC areas and measurements from the aircraft flights are used to compare cloud, aerosol, and boundary layer conditions inside and outside of POCs and conditions found across individual POC cases. POCs are observed in boundary layers with a wide range of inversion heights (1250 to 1600 m) and surface wind speeds (5 to 11 m s−1) and show no remarkable difference from the observed surface and free tropospheric conditions during the two months of the field campaign. In all cases, compared to the surrounding overcast region the POC boundary layer is more decoupled, supporting both thin stratiform and deeper cumulus clouds. Although cloud-base precipitation rates are higher in the POC than the overcast region in each case, a threshold precipitation rate that differentiates POC precipitation from that in overcast precipitation does not exist. Mean cloud-base precipitation rates in POCs can range from 1.7 to 5.8 mm d−1 across different POC cases. The occurrence of heavy drizzle (> 0 dBZ) lower in the boundary layer better differentiates POC precipitation from precipitation in the surrounding overcast regions, likely leading to the more active cold pool formation in POCs. Cloud droplet number concentration is at least a factor of eight smaller in the POC clouds, and the ratio of drizzle water to cloud water in POC clouds is over an order of magnitude larger than that in overcast clouds, indicating an enhancement of collision coalescence processes in POC clouds. Despite large variations in the accumulation-mode aerosol concentrations (65 to 324 cm−3) observed in the surrounding overcast region, the accumulation-mode aerosol concentrations observed in the subcloud layer of all five POCs exhibit a much narrower range (24 to 40 cm−3), and cloud droplet concentrations within the cumulus updrafts originating in this layer reflect this limited variability. Above the POC subcloud layer exists an ultraclean layer with accumulation-mode aerosol concentrations < 5 cm−3, demonstrating that in-cloud collision coalescence processes efficiently remove aerosols. It also suggests that the major source of accumulation-mode aerosols, and hence of cloud condensation nuclei in POCs, is the ocean surface, while entrainment of free tropospheric aerosol is weak. The measurements also suggest that at approximately 30 cm−3 a balance of surface source and coalescence scavenging sinks of accumulation-mode aerosols maintain the narrow range of observed subcloud aerosol concentrations.

We examined the effect of daily fat supplementation on intestinal gene expression and protein synthesis and plasma levels of apolipoprotein A-IV (apo A-IV). Rats were fasted overnight and then given intragastric bolus infusion of either saline or fat emulsion after 0, 1, 2, 4, 8, or 16 days of similar daily feedings. Four hours after the final saline or fat infusion, plasma and jejunal mucosa were harvested; plasma levels of apo A-IV, triglycerides, and leptin were measured, as well as mucosal apo A-IV mRNA levels and biosynthesis of apo A-IV protein. In response to fat, plasma apo A-IV showed an initial 40% increase compared with saline-injected control rats; with continued daily fat feeding, the plasma A-IV response showed rapid and progressive diminution such that by 4 days, plasma A-IV was not different between fat- and saline-fed groups. Jejunal mucosal apo A-IV synthesis and mRNA levels also showed time-dependent refractoriness to fat feeding. However, the kinetics of this effect were considerably slower than in the case of plasma, requiring 16 days for completion. There was no correlation between plasma leptin or triglyceride levels and intestinal apo A-IV synthesis or plasma apo A-IV. These results indicate rapid, fat-induced, posttranslational adapation of plasma apo A-IV levels and a slower, but similarly complete pretranslational adaptation of intestinal apo A-IV production, which are independent of plasma levels of leptin.

Background. Cystic fibrosis patients have chronic bacterial infections of the respiratory tract, most commonly Pseudomonas aeruginosa. Although controversial, administration of antibiotic therapy during acute pulmonary exacerbations is standard practice. Fluoroquinolones are currently not indicated for use in young children because of the observation of arthropathy and damage to growing cartilage in beagle puppies. Because of its activity against P. aeruginosa and excellent oral bioavailability, ciprofloxacin offers a unique therapeutic alternative for this patient population. Objective. This prospective, randomized, double blind study compared the efficacy and safety of sequential intravenous/oral ciprofloxacin vs. ceftazidime/tobramycin in hospitalized pediatric cystic fibrosis patients with an acute pulmonary exacerbation associated with P. aeruginosa infection. Methods. One hundred thirty patients (ages 5 to 17 years) were randomized to receive either iv ciprofloxacin 10 mg/kg every 8 h for 7 days followed by oral ciprofloxacin 20 mg/kg every 12 h for a minimum of 3 days or iv ceftazidime 50 mg/kg every 8 h plus iv tobramycin 3 mg/kg every 8 h for a minimum of 10 days. Clinical, bacteriologic and safety responses were assessed throughout the study. Results. All 84 patients (median age, 11 years; range, 5 to 17 years) valid for efficacy in both treatment groups demonstrated clinical improvement. Five patients experienced clinical relapses (3 ciprofloxacin, 2 ceftazidime/tobramycin) by the 2- to 4-week follow-up. Intent-to-treat analysis demonstrated similar clinical findings between the two treatment groups at both the end of therapy and follow-up. Clinical improvement correlated with improvement in pulmonary function studies and the acute clinical scoring system but not with bacteriologic eradication of Pseudomonas. DNA profiles demonstrated that irrespective of colony morphology, usually one clonal strain was associated with each patient's pulmonary exacerbation. Treatment-associated musculoskeletal events occurred with equal frequency (22% vs. 21%) in both study drug groups (n = 129), and arthralgias were within the range of rates for cystic fibrosis arthropathy. None of these events required study drug discontinuation. Conclusion. Sequential iv/oral ciprofloxacin monotherapy offers a safe and efficacious alternative to standard parenteral therapy for acute pulmonary exacerbations in pediatric cystic fibrosis patients.

Over the southeastern Pacific (SEP), droplet concentration (Nd) in the typically unpolluted marine stratocumulus west of 80° W (> 1000 km offshore) is periodically strongly enhanced in zonally-elongated "hook"-shaped arcs that increase albedo. Here, we examine three hook events using the chemistry version of the Weather Research and Forecasting model (WRF-Chem) with 14 km horizontal resolution, satellite data and aircraft data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx). A particularly strong hook yields insights to the development, decay, and radiative impact of these features. Hook development occurs with Nd increasing to polluted levels over the remote ocean primarily due to entrainment of cloud condensation nuclei (CCN) from the free troposphere (FT). The feature advects northwestward until the FT CCN source is depleted, after which Nd decreases over a few days due to precipitation and dilution. The model suggests that the FT CCN source supplying the hook consists of high concentrations of small accumulation mode aerosols that contribute a relatively small amount of aerosol mass to the MBL. The aerosol particles originate mainly from a pulse of offshore flow that transports Santiago region (33–35° S) emissions to the marine FT. To provide a sustained hook CCN source, the FT transport of pollution plumes to the remote ocean requires strong, deep offshore flow. Such flow is favored by a trough approaching the South American coast and a southeastward shift of the climatological subtropical high pressure system. The model simulations show precipitation suppression in the hook and a corresponding increase in liquid water path (LWP) compared with a simulation without anthropogenic sources. LWP also increases in time as the hook evolves due to increasing stability and decreasing subsidence. WRF-Chem suggests that DMS significantly influences the aerosol number and size distributions in a hook, but that hooks do not form without FT CCN. The Twomey effect contributes ~ 50–70% of the albedo increase due the presence of the hook, while secondary aerosol indirect effects and meteorological influences also contribute significantly. The source of hook aerosols is difficult to determine with the available observations alone. The model explains the observations and puts them in context of the factors influencing hook formation. Two other weaker hooks during VOCALS-REx are not as well simulated but are also associated with FT offshore flow near Santiago. Hooks demonstrate the importance of free-tropospheric transport of aerosols in modulating the droplet concentration in the southeastern Pacific stratocumulus deck, and present a formidable challenge to simulate accurately in large scale models.

A case-control study was performed in a community-based nonteaching hospital to assess patient risk factors for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa. Fifty-five patients who were hospitalized between July 1, 1993 and December 31, 1993 and who had P. aeruginosa recovered from a clinical specimen were included in the analysis. Two patient populations were designated based on the fluoroquinolone susceptibility of their P. aeruginosa isolates. Statistical evaluation using univariate analysis of demographic and clinical data from the 42 patients with quinolone-susceptible P. aeruginosa and the 13 patients with quinolone-resistant P. aeruginosa demonstrated that prior receipt of a fluoroquinolone was the only significant risk factor for the subsequent emergence of fluoroquinolone resistance among P. aeruginosa isolated from patients hospitalized in this small community-based institution (p = 0.0196). Multivariate analysis supported the finding that prior receipt of a fluoroquinolone was the major risk factor for the isolation of fluoroquinolone-resistant P. aeruginosa (p = 0.0004); isolation of this Gram-negative bacillus from sputum (p = 0.0306) and a history of recent surgery (p = 0.0058) were also significantly associated as risk factors for resistance.

Chloride anion is critical for hypochlorous acid (HOCl) production and microbial killing in neutrophil phagosomes. However, the molecular mechanism by which this anion is transported to the organelle is poorly understood. In this report, membrane-enclosed and functionally active phagosomes were isolated from human neutrophils by using opsonized paramagnetic latex microspheres and a rapid magnetic separation method. The phagosomes recovered were highly enriched for specific protein markers associated with this organelle such as lysosomal-associated membrane protein-1, myeloperoxidase (MPO), lactoferrin, and NADPH oxidase. When FITC–dextran was included in the phagocytosis medium, the majority of the isolated phagosomes retained the fluorescent label after isolation, indicative of intact membrane structure. Flow cytometric measurement of acridine orange, a fluorescent pH indicator, in the purified phagosomes demonstrated that the organelle in its isolated state was capable of transporting protons to the phagosomal lumen via the vacuolar-type ATPase proton pump (V-ATPase). When NADPH was supplied, the isolated phagosomes constitutively oxidized dihydrorhodamine 123, indicating their ability to produce hydrogen peroxide. The preparations also showed a robust production of HOCl within the phagosomal lumen when assayed with the HOCl-specific fluorescent probe R19-S by flow cytometry. MPO-mediated iodination of the proteins covalently conjugated to the phagocytosed beads was quantitatively measured. Phagosomal uptake of iodide and protein iodination were significantly blocked by chloride channel inhibitors, including CFTRinh-172 and NPPB. Further experiments determined that the V-ATPase-driving proton flux into the isolated phagosomes required chloride cotransport, and the cAMP-activated CFTR chloride channel was a major contributor to the chloride transport. Taken together, the data suggest that the phagosomal preparation described herein retains ion transport properties, and multiple chloride channels including CFTR are responsible for chloride supply to neutrophil phagosomes.

The structure and absolute configuration of (−)- cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine (FTC), has been determined by X-ray crystallographic analysis. The results confirm that the L-isomer of the nucleoside analogue is the most active enantiomer and that the correct absolute configuration of (−)-FTC is 5-fluoro-(2′R,5′S)-(−)-1-[2-hydroxymethyl)oxathiolan-5-yl]-fluorocytosine. The two molecules in the asymmetric unit show conformations that combine conformational features of two other classes of potent antiviral nucleosides. Both oxathiolane rings have the 3′-sulphur atom in nearly perfect S3′- exo envelope conformations, similar to what is observed for 3′-azido-3′-deoxythymidine (AZT) and 2′,3′-dideoxycytidine. One of the two molecules has a glycosylic link conformation in which the base is eclipsed with the C5′-O1′ bond. This mimics the high- anti conformation that has been observed in the structures of several 2′,3′-didehydro-2′,3′-dideoxypyrimidine nucleosides but is inaccessible for saturated pyrimidine nucleosides. However, the observed conformations cannot be superimposed adequately with other active antiviral nucleosides to suggest a common ‘active site’ conformation.

We are reporting on a nosocomial outbreak of 213 cases of vancomycin-resistant enterococcus infection involving 2,812 enterococcal isolates from patients over a period of 36 months. In 1990, the Enterococcus faecium vancomycin susceptibility rate was found to be 85.7% (36 of 42 cases), and an incidence of 10.9% (42 of 383) was noted. The 1991 data showed E. faecium with a vancomycin susceptibility rate of 61.8% (110 of 178) and an incidence of 26.0% (178 of 684). Subsequently, in 1992, the incidence of E. faecium increased to 34.0% (599 of 1,745), with a decreased vancomycin susceptibility rate of 25.8% (155 of 599). The E. faecalis vancomycin susceptibility rate remained near 97% (1,768 of 1,823) over the 36-month period. Of 115 vancomycin-resistant enterococcus (VRE) clinical isolates identified by the MicroScan MIC Combo-6 panels (Baxter Healthcare, Sacramento, Calif.), the agar dilution method indicated the resistance rate to be 92.3% (106 of 115) (high level), 3.5% (4 of 115) midlevel, and 3.5% (4 of 115) (low level). Genotypic characterization of 32 different VRE isolates by field-inversion gel electrophoresis demonstrated 19 dissimilar restriction endonuclease patterns, with 9 patterns associated with VRE quinolone resistance. Statistical analysis of case-control data for 32 patients with VRE infections indicated a positive association with intrabdominal surgical procedures (odds ratio, 24.12), multidrug therapy (odds ratio, 37.80), preexposure to vancomycin (odds ratio, 20.21), and death (odds ratio, 17.50).

Alcohol abuse is associated with immunosuppressive and infectious sequelae. Particularly, alcoholics are more susceptible to pulmonary infections. In this report, gene transcriptional profiles of primary human airway epithelial cells exposed to varying doses of alcohol (0, 50, and 100 mM) were obtained. Comparison of gene transcription levels in 0 mM alcohol treatments with those in 50 mM alcohol treatments resulted in 2 genes being upregulated and 16 genes downregulated by at least 2-fold. Moreover, 0 mM and 100 mM alcohol exposure led to the upregulation of 14 genes and downregulation of 157 genes. Among the upregulated genes, glucocorticoid-induced leucine zipper (GILZ) responded to alcohol in a dose-dependent manner. Moreover, GILZ protein levels also correlated with this transcriptional pattern. Lentiviral expression of GILZ small interfering RNA in human airway epithelial cells diminished the alcohol-induced upregulation, confirming that GILZ is indeed an alcohol-responsive gene. Gene silencing of GILZ in A549 cells resulted in secretion of significantly higher amounts of inflammatory cytokines in response to IL-1β stimulation. The GILZ-silenced cells were more resistant to alcohol-mediated suppression of cytokine secretion. Further data demonstrated that the glucocorticoid receptor is involved in the regulation of GILZ by alcohol. Because GILZ is a key glucocorticoid-responsive factor mediating the anti-inflammatory and immunosuppressive actions of steroids, we propose that similar signaling pathways may play a role in the anti-inflammatory and immunosuppressive effects of alcohol.

CFTR transports chloride anions necessary for HOCl production and optimal microbicidal activity in human neutrophil phagosomes. Chloride serves as a critical component of innate host defense against infection, providing the substrate for MPO-catalyzed production of HOCl in the phagosome of human neutrophils. Here, we used halide-specific fluorescent sensors covalently coupled to zymosan particles to investigate the kinetics of chloride and iodide transport in phagosomes of human neutrophils. Using the self-ratioable fluorescent probe specific for chloride anion, we measured chloride dynamics within phagosomes in response to extracellular chloride changes by quantitative fluorescence microscopy. Under the experimental conditions used, normal neutrophils showed rapid phagosomal chloride uptake with an initial influx rate of 0.31 ± 0.04 mM/s (n=5). GlyH-101, a CFTRinh, decreased the rate of uptake in a dose-dependent manner. Neutrophils isolated from CF patients showed a significantly slower rate of chloride uptake by phagosomes, having an initial influx rate of 0.043 ± 0.012 mM/s (n=5). Interestingly, the steady-state level of chloride in CF phagosomes was ∼26 mM, significantly lower than that of the control (∼68 mM). As CFTR transports chloride as well as other halides, we conjugated an iodide-sensitive probe as an independent approach to confirm the results. The dynamics of iodide uptake by neutrophil phagosomes were monitored by flow cytometry. CFTRinh172 blocked 40–50% of the overall iodide uptake by phagosomes in normal neutrophils. In a parallel manner, the level of iodide uptake by CF phagosomes was only 20–30% of that of the control. Taken together, these results implicate CFTR in transporting halides into the phagosomal lumen.

TOPIC: Access and utilization of mental health services for Latino children. PURPOSE: As Latino children may experience higher rates of unmet needs, this article examines the current literature for the reasons for the disparity and the barriers to the utilization of mental health services for Latino children. SOURCES: An integrative literature review was undertaken from child psychiatry and nursing. CONCLUSIONS: The literature confirmed a pattern of underutilization of mental health services by Latino children, but did not completely address the reasons for the disparity. Suggested barriers were language and cultural issues. Gaps in the literature include a lack of agreement for definition of a mental health problem and the tools to identify these, insufficient studies into the barriers for Latino children in the access and utilization of mental health services, and cultural and language issues related to Latino research.

Recently, I experienced cancer from the other side: I have had the privilege of sharing the cancer experience with an intimate other. It was while I lived through this experience, this hand-in-hand, heart-to-heart and soul-by-soul walk with my husband that I really learned what I thought I already knew about how oncology nurses alleviate suffering, help heal and lessen the burden of the cancer illness. The purpose of this paper is to provide the oncology nurse with a portal into a lived experience of a person dying of cancer and to confirm what we do know, describe what we do not know and to lovingly challenge some of our assumptions so that we may become better students of our real teachers: our patients.

A focus group methodology was employed to identify personal, social, and environmental factors that affect smoking cessation in persons with serious mental illness. Four focus groups were held: two for those who had attempted to quit smoking and two for those who had never attempted to quit. Smoking is central to daily survival in patients with serious mental illness. Social and environmental reinforcement can both assist and hinder efforts to stop smoking. Smoke-free environments influence decisions to quit smoking if positive social comparisons with nonsmokers occur. Peer modeling and interpersonal connections with nonsmokers can offer links to forming supportive nonsmoking relationships.

Production of hypochlorous acid (HOCl) in neutrophils, a critical oxidant involved in bacterial killing, requires chloride anions. Because the primary defect of cystic fibrosis (CF) is the loss of chloride transport function of the CF transmembrane conductance regulator (CFTR), we hypothesized that CF neutrophils may be deficient in chlorination of bacterial components due to a limited chloride supply to the phagolysosomal compartment. Multiple approaches, including RT-PCR, immunofluorescence staining, and immunoblotting, were used to demonstrate that CFTR is expressed in resting neutrophils at the mRNA and protein levels. Probing fractions of resting neutrophils isolated by Percoll gradient fractionation and free flow electrophoresis for CFTR revealed its presence exclusively in secretory vesicles. The CFTR chloride channel was also detected in phagolysosomes, a special organelle formed after phagocytosis. Interestingly, HL-60 cells, a human promyelocytic leukemia cell line, upregulated CFTR expresssion when induced to differentiate into neutrophils with DMSO, strongly suggesting its potential role in mature neutrophil function. Analyses by gas chromatography and mass spectrometry (GC-MS) revealed that neutrophils from CF patients had a defect in their ability to chlorinate bacterial proteins from Pseudomonas aeruginosa metabolically prelabeled with [(13)C]-l-tyrosine, unveiling defective intraphagolysosomal HOCl production. In contrast, both normal and CF neutrophils exhibited normal extracellular production of HOCl when stimulated with phorbol ester, indicating that CF neutrophils had the normal ability to produce this oxidant in the extracellular medium. This report provides evidence which suggests that CFTR channel expression in neutrophils and its dysfunction affect neutrophil chlorination of phagocytosed bacteria.

Top of pageAbstract Human mesenchymal stem cells (hMSCs) from adult bone marrow can differentiate into a variety of different cell types including airway epithelial cells, suggesting the theraputic potential of stem cells in tissue injury repair. However, approaches for the efficient recruitment of hMSCs to specific sites have not been established. To this end, we have investigated whether hMSCs express the N-formyl peptide receptor (FPR), which is typically expressed in polymorphonuclear leukocytes and is responsible for the neutrophil chemotactic response. Reverse transcription PCR using FPR specific primers resulted in a positive amplification of this mRNA. Sequencing of the amplicon proved 100% homology to the published FPR sequence. Immunofluorescence staining using a monoclonal antibody against human FPR and flow cytometric analyses demonstrated that hMSCs express FPR at the protein level. Actin polymerization after formylated peptide stimulation is one of the basic cellular responses indicative of the FPR function. We incubated hMSCs with 100nM of N-formyl methionyl leucyl phenylalanine (fMLP). Staining with phalloidin-conjugated fluorescein and flow cytometric analyses showed significant F-actin polymerization in hMSCs. Also, hMSCs were attracted toward fMLP gradients in Boyden chambers and binding of flourescein-labeled formyl-Nle-Leu-Phe-Nle-Tyr-Lys displayed the existence and functionality of the receptor in hMSCs. Thus, we conclude that hMSCs express functional formyl peptide receptors on their surface membrane and are capable of chemotaxis toward their ligand. The expression of the N-formyl peptide receptor on hMSCs, cells not normally associated with immune responses, could serve as a mechanism of directing stem cells to the sites of inflammation. Therefore, endogenous expression or over-expression of the receptor within hMSCs could be manipulated in a manner to target these cells to specific inflammatory sites, such as the lungs in cystic fibrosis.

Integration of a therapeutic gene into the host cell genome permits stable expression of the gene product in the target cells and its progeny. However, non-directional integration of any given gene can pose the risk of activating tumor genes or silencing tumor suppressor genes. Therefore, including a safety-control element into integrating vector systems is an important advance towards safer human gene therapy. Here, we report on a gene expression cassette that can be potentially exploited in integrating vector systems to eliminate post-therapeutic tumorigenesis. The Herpes simplex virus thymidine kinase (hsvTK) gene under the transcriptional control of the human telomere reverse transcriptase promoter (hTERTp) was incorporated into a self-inactivating HIV-based lentiviral vector. The hTERT promoter is silent in normal somatic cells and re-activated in tumor cells. Therefore, normal gene-corrected cells should not express hsvTK from the promoter. However, if some gene-corrected cells subsequently become tumorigenic and the hTERT promoter is re-activated, application of ganciclovir (GCV), a clinically used antiviral drug, will achieve selective deletion of the cancerous cells. Our experimental data indicated that the hTERTp-hsvTK cassette in the lentiviral vector was sufficient to differentiate between tumor cells and normal cells, thus eradicating tumor cells selectively in vitro and in vivo. These results proved the principle of using the element in integrating vectors for safer gene delivery. (Cancer Sci 2005; 96: 607 –613)

We examined the effect of ileal infusions of lipid emulsion on mRNA levels and biosynthesis of apolipoprotein A-IV (apo A-IV) in jejunal Thiry-Vella fistulas in rats. The rats were surgically prepared with jejunal Thiry-Vella fistulas; after recovery they were deprived of food, equipped with ileal infusion cannulas, then given 8 hr ileal infusions of fatty acid/monoglyceride emulsions. Mucosal synthesis and transcript levels of apo A-IV in the Thiry-Vella loop were then measured. Lipid infusion produced a two-fold stimulation in incorporation of 3H-leucine into apo A-IV-specific protein, but had no significant effect on apo A-IV mRNA levels. These results support the hypothesis that a lipid-elicited, distal gut-derived, systemic signal stimulates the production of apo A-IV by a post-transcriptional mechanism.

Cystic fibrosis patients have chronic bacterial infections of the respiratory tract, most commonly Pseudomonas aeruginosa. Although controversial, administration of antibiotic therapy during acute pulmonary exacerbations is standard practice. Fluoroquinolones are currently not indicated for use in young children because of the observation of arthropathy and damage to growing cartilage in beagle puppies. Because of its activity against P. aeruginosa and excellent oral bioavailability, ciprofloxacin offers a unique therapeutic alternative for this patient population.This prospective, randomized, double blind study compared the efficacy and safety of sequential intravenous/oral ciprofloxacin vs. ceftazidime/tobramycin in hospitalized pediatric cystic fibrosis patients with an acute pulmonary exacerbation associated with P. aeruginosa infection.One hundred thirty patients (ages 5 to 17 years) were randomized to receive either i.v. ciprofloxacin 10 mg/kg every 8 h for 7 days followed by oral ciprofloxacin 20 mg/kg every 12 h for a minimum of 3 days or i.v. ceftazidime 50 mg/kg every 8 h plus i.v. tobramycin 3 mg/kg every 8 h for a minimum of 10 days. Clinical, bacteriologic and safety responses were assessed throughout the study.All 84 patients (median age, 11 years; range, 5 to 17 years) valid for efficacy in both treatment groups demonstrated clinical improvement. Five patients experienced clinical relapses (3 ciprofloxacin, 2 ceftazidime/tobramycin) by the 2- to 4-week follow-up. Intent-to-treat analysis demonstrated similar clinical findings between the two treatment groups at both the end of therapy and follow-up. Clinical improvement correlated with improvement in pulmonary function studies and the acute clinical scoring system but not with bacteriologic eradication of Pseudomonas. DNA profiles demonstrated that irrespective of colony morphology, usually one clonal strain was associated with each patient's pulmonary exacerbation. Treatment-associated musculoskeletal events occurred with equal frequency (22% vs. 21%) in both study drug groups (n = 129), and arthralgias were within the range of rates for cystic fibrosis arthropathy. None of these events required study drug discontinuation.Sequential i.v./oral ciprofloxacin monotherapy offers a safe and efficacious alternative to standard parenteral therapy for acute pulmonary exacerbations in pediatric cystic fibrosis patients.

Neutrophil responses to α-N-formyl-L-Met- L-Leu-L-Phe (fMLF) are modulated by inhibitors of surface membrane neutral endopeptidase (NEP), such as phosphoramidon (PPAD). Because receptor recycling is presumably required for a sustained cellular response, the effect of PPAD on receptor reexpression was examined. After down-regulation of surface fMLF receptors by fMLF, PPAD blocked the normal reexpression of surface receptors in a manner that was related to the time of prior exposure to fMLF. Internalized fML[3H]F was hydrolyzed by NEP at a rate comparable to the rate of receptor reexpression at the cell surface, suggesting that ligand hydrolysis is rate limiting. To test this hypothesis, cells were incubated with fluorescein-labeled formyl-Met-Leu-Phe-Nle-Tyr-Lys at 15°C. After binding was complete, but before internalization of receptor-ligand complexes, high-affinity antifluorescein antibody F(ab’)2 fragments were added and the cells incubated at 37°C for 60 min in the presence of PPAD. Under these conditions, the inhibitory effects of PPAD were largely reversed and nonimmune F(ab’)2 fragments were without effect.

Aim To establish whether parents feel that they were told about their child9s hearing loss in a way that accorded with the recommendations laid down in the objectives of a family friendly service. Method The North West Paediatric Audiology Audit Group sent out questionnaires to parents of children who had had their sensorineural hearing loss confirmed more than 6 months and less than 3 years previously. This was a repeat of a similar study carried out in 2005. Questionnaires were sent out between January 2009 and August 2009 with a reminder being sent to non-responders. Results 16 trusts took part, 123 families were contacted and 67 forms were returned (54.5%). 62% of parents remembered being accompanied to the appointment; 82% remembered that the clinician introduced themselves; 92% said that their preferred language was used during the appointment; 86% of parents were either satisfied or very satisfied with the way that the news was given; 94% felt that they had enough privacy at the time the news was given; 81% said they were given enough time to ask questions; 71% remembered being given a contact name and telephone number; 77% felt that the amount of information given to them was about right; 74% felt that the information given was easy or very easy to understand; 70% remembered being given written information to take away with them. Conclusion Newborn hearing screening is now in place across England and most new cases of confirmed sensorineural hearing loss are in babies. All clinicians who share the news should have been training to give the news. The results were all improved compared with those in 2005 but none achieved the exacting standards set of 100%.

The regulation of prostacyclin (PGI2) synthesis by cultured human umbilical vein endothelium (HUVEC) was investigated. HUVEC monolayer generation of PGI2 was monitored by RIA of 6-keto PGF1 alpha and dose-dependent increases observed with human alpha- and gamma-thrombins, histamine, or arachidonate. Alpha thrombin (10 nM) produced levels of 6-keto PGF1 alpha approximating responses with 1 microM gamma-thrombin, 5 microM arachidonate, or 10 microM histamine. Diisopropyl phosphorofluoridate-inactivated alpha-thrombin did not stimulate PGI2 release, demonstrating that catalytic activity was required for thrombin-stimulated PGI2 release. Sodium fluoride (NaF), at concentrations known to activate guanine nucleotide regulatory proteins (G proteins), directly stimulated HUVEC PGI2 synthesis in a dose-dependent and time-dependent manner (20 mM NaF, 4.4 +/- 0.5-fold increase at 10 min, 11.9 +/- 1.5-fold increase at 30 min). Neither alpha-thrombin nor NaF-stimulated PGI2 release was dependent upon the availability of extracellular Ca++). The hypothesis that G proteins are involved in agonist-stimulated PGI2 synthesis was further supported by studies using digitonin-permeabilized HUVEC monolayers challenged with another G protein activator, guanosine 5'-0-3-thiotrisphosphate (GTP gamma S), which effected significant dose-dependent increases in PGI2 synthesis compared with control levels of 6-keto PGF1 alpha. In contrast, the G-protein inhibitor GDP beta S, (guanosine 5'-0-2-thiodiphosphate), attenuated alpha-thrombin-mediated prostaglandin generation. Treatment of HUVEC monolayers with pertussis toxin (1 microgram/ml) did not inhibit the PGI2 synthesis stimulated by either alpha-thrombin, NaF, or histamine but catalyzed the ADP ribosylation of a 40 kDa membrane protein which cross-reacted with antisera against a synthetic peptide corresponding to an amino acid sequence common to the alpha-subunit of other G-proteins. Preincubation of HUVEC microsomal membranes with alpha-thrombin diminished pertussis toxin-catalyzed ADP ribosylation in a time-dependent manner. These data suggest that thrombin stimulation of PGI2 synthesis by HUVEC monolayers requires the catalytically functional enzyme and further suggests that the thrombin-occupied receptor is coupled to phospholipase activities by a pertussis toxin-insensitive guanine nucleotide regulatory protein in human endothelial cell membranes.

Cystic fibrosis (CF), the most common genetic disease in Caucasians, is caused by mutations of the gene encoding the CF transmembrane conductance regulator (CFTR), a cAMP-regulated chloride channel. CF has long been recognized as an epithelial disease whose most severe complications often occur in the lung. The clinical manifestations include persistent bacterial infection, prominent neutrophil infiltration and small airway obstruction. Even though dramatic advances have been made towards understanding of CF pathogenesis, the link between the CFTR chloride channel defect and a clinical defect in bacterial eradication has not been fully established. Our published data demonstrated that CFTR is expressed in human neutrophils and their phagolysosomes. CF neutrophils are defective in the chlorination of phagocytosed Pseudomonas aeruginosa (PAO1), indicating defective intraphagolysosomal hypochlorous acid (HOCl) production. In the current report, we assessed the bacterial killing abilities of neutrophils from CF and normal individuals. Percoll-purified peripheral blood neutrophils were incubated with opsonized PAO1 at a ratio of 1:1 or 1:50. To define the role of chloride in the killing process, two different Ringer’s buffers with either 0 mM chloride or 135 mM chloride were exploited. At various time points (0, 15, 30 and 60 minutes) after incubation of neutrophils with bacteria, samples were aliquoted to assay for viable bacteria. After correction for bacterial growth over the experimental period, the bacterial viability at each time point relative to that of the initial value was obtained. Two-way ANOVA tests indicated that CF neutrophils had a significantly lower initial rate of killing of PAO1 than that in normal controls. This defect is more pronounced under the condition of high bacterial load and low extracellular chloride. Surprisingly, the low extracellular chloride significantly affected neutrophil-mediated bacterial killing even for the normal neutrophils, suggesting the dependence of this ion in the killing process. Our data provide evidence to suggest the potential role of CFTR in supplying intraphagolysosomal chloride to produce hypochlorous acid (HOCl), an oxidant essential for the killing of HOCl-sensitive bacteria.

Numerous commercial and military applications exist for guest–host liquid crystal (LC) devices operating in the near- to mid-IR region. Progress in this area has been hindered by the severe lack of near-IR dyes with good solubility in the LC host, low impact on the inherent order of the LC phase, good thermal and chemical stability, and a large absorbance maximum tunable by structural modification over a broad range of the near-IR region. Transition metal complexes based on nickel, palladium, or platinum dithiolene cores show substantial promise in meeting these requirements. These new dye complexes are extraordinarily stable, possess liquid crystalline phases in their own right with the proper terminal functional groups, and can have melting points below room temperature. The latter property is especially significant for producing liquid crystal/dye mixtures with both high dye concentration and good resistance to phase separation. Because transition metal dithiolenes are zerovalent, they can exhibit high...

Bone marrow mesenchymal stem cells (MSCs) have been shown to differentiate into pulmonary epithelial cells in animal models. To explore whether human MSCs can undergo differentiation into airway epithelia, which can be exploited as a novel gene therapy strategy for cystic fibrosis (CF), human MSCs expressing green florescent protein (GFP) were mixed with primary human airway epithelial cells in a ratio of 1:5, 1:10, or 1:20, and seeded on a semi-permeable filter membrane coated with human placenta collagen type VI. The cells were cultured at an air-liquid interface and were able to maintain the apical surface dry after one to two weeks with transepithelial resistance greater than 700 Ohms, suggesting the formation of tight junctions. Immunofluorescent staining with an antibody against cytokeratin 18 (CK18) demonstrated that the stem cells co-cultured with human airway cells expressed this epithelium-specific marker, whereas prior to the culture, there is no detectable CK18 expression by this approach. Morphologically, the GFP-labeled stem cells converted their original thin-spindle fibroblast shape or flat polygonal cell shape to a typical epithelial cuboidal shape with an accessory structure like cilia by confocal microscopy, suggesting that the hMSCs in the co-culture system transdifferentiate into airway epithelial cells. To confirm the finding, we further did immunostaining with an antibody against occludin, an epithelial tight junction protein. Flow cytometry and fluorescent microscopy showed that ~10% of the initially loaded GFP-MSCs express this critical epithelial marker. By cell sorting, we isolated the co-cultured hMSCs, and RT-PCR was performed with primers specific to human CFTR. The results demonstrated that the air-liquid culture induces hMSCs to express the CFTR gene. Furthermore, co-culture of normal hMSCs with CF airway epithelial cells resulted in the wild-type CFTR expression. More importantly, the MSCs isolated from CF patients were able to be gene-corrected. In vitro differentiation assays proved that the CFTR gene-corrected CF MSCs still possess their naive multipotency, such as differentiation along osteogenic, adipogenic, and chondrogenic pathways. The gene-corrected CF MSCs were able to contribute to apical Cl- secretion by chloride efflux assay in response to cAMP agonists. Conditions to increase the efficacy of MSC differentiation are currently under investigation. Therefore, we conclude that bone marrow mesenchymal stem cells may have potential applications in treating human airway diseases, such as CF.